Aromatic polycarbonate resins are known engineering thermoplastics which can be molded into clear transparent articles that are suitable for various commercial purposes. The aromatic polycarbonates can be prepared by known processes, such as those described in the patent literature, for example, U.S. Pat. Nos. 3,153,008; 4,018,750; 4,123,436; and 4,469,861.
Many present commercial applications make desirable the good thermal and physical properties that are characteristic of aromatic polycarbonates. However, because of the size and complexity of the molds that are required in at least some of the cases, it would be advantageous to improve the melt processability of the polymer to achieve greater ease of flow through the extruder and into the mold. One way to achieve this is to use a polymer of lower molecular weight and, correspondingly, lower intrinsic viscosity. Typically, however, there are manufacturing problems associated with the preparation and isolation of commercial scale quantities of lower molecular weight aromatic polycarbonates, for instance, poly(bisphenol-A carbonates) having an intrinsic viscosity (I.V.) of less than 0.45 as measured in solution in chloroform (CHCl.sub.3) at 25.degree. C.
Thus, it has heretofore often been necessary to add agents which function to enhance the melt flow properties of the polymer. For instance, British Pat. No. 1,544,788 discloses high molecular weight aromatic polycarbonate resins prepared with chain stoppers comprised of a C.sub.9 to C.sub.26 carboxylic acid and a diphenol in combination. The polymer is described as having good mold release and mechanical properties. To improve the flow properties, they recommend the use of small amounts of a compound containing three or more functional groups, such as hydroxy groups (page 2, second column, lines 80-110 of the British patent).